As far as a pattern is concerned, I watched one of Martha Pullens videos years ago, that had you do all the smocking on a piece of yard goods that ended up being larger than the pattern piece you are using. Take the pattern piece you want to use, and trace it onto light weight Iron-on interfacing. Cut it out and iron it to the wrong side of the smocked fabric, then cut it out, and now you have a smocked piece that is just the right shape. That is how she made a childs dress and a doll dress with smocking. Both had smocked bodice fronts, but smooth skirts and collars.